Potato Flea Beetles: Biology and Control

Extension Bulletin 1198E

POTATO FLEA BEETLES: BIOLOGY AND CONTROL

Potato flea beetles can be serious pests of a wide Flea beetles spend the winter as adults in protected variety of vegetable crops, especially in western Wash- places, such as under leaves and along ditchbanks. ington. In addition to potato, they also attack tomato, They emerge in the spring and feed on weeds, grasses, pepper, eggplant, bean, cabbage, corn, cucumber, let- and wild vegetation until garden plants are available. tuce, radish, spinach, and several other plants. Potato They lay their tiny eggs on the soil around the plants. and tomato are generally the most seriously affected. The larvae (immature stages) spend their lives feeding on underground portions of host plants. Description and Life History The larvae of flea beetles are small, whitish, delicate, Two species of flea beetles are of major concern. These cylindrical grubs. Their development takes place in are the tuber flea beetle, Epitrix tuberis, and the west- the soil and may take 3 to 4 weeks to complete. ern potato flea beetle, Epitrix subcrinata (Fig. 1). The Pupation also occurs in the soil and takes from 7 to adult tuber flea beetle is oval and black with reddish 10 days. There are one to two generations per year antennae and legs. It is approximately 1/16 inch long and sometimes a partial third. (1.5Ð2mm). The western potato flea beetle somewhat resembles the tuber flea beetle except that it is a shiny Damage bronze. The femur or midportion of the hind leg of these beetles is greatly enlarged, giving them the ability Adults feed on the foliage of plants. Feeding damage to jump considerable distances when they are disturbed. consists of small round holes about 1/16 to 1/8 inch in diameter. When feeding is extensive, the damaged foliage appears to have been “blasted” with a shotgun causing severe stress or death of the plant (Fig. 2). Larvae feed on underground parts of plants, such as roots and tubers. Western potato flea beetle larvae largely restrict their feeding to the roots of potatoes but occasionally attack the tuber. Tuber flea beetle larvae feed extensively on potato tubers. The damage appears as a complex of winding grooves on the sur- face of the potato. Grooves are usually less than 1/16 inch in diameter and very shallow. Larvae may also bore into the tuber, and this appears as a pinhole ex- tending 1/2 inch or less into the fleshy portion of the potato—occasionally holes will be deeper. Holes are Figure 1—Adult tuber flea beetle. commonly filled with a dark material which stains Photo—Ken Grey Collection the white flesh of the tuber. Tuber flea beetle damage

COOPERATIVE EXTENSION to the tuber is usually not significant. However, dam- Control age does make the potatoes quite unsightly (Fig. 3). Feeding also makes an easy entry for many microor- To obtain information on current status of products ganisms that may cause rotting or reduce the storage to control these beetles, check with your local county potential of the potato. If beetle damage does not re- extension agent, who has access to the annually duce the potato to an inedible state, damage and stain revised Pacific Northwest Insect Management Hand- can be easily removed by extra peeling. book. We did not list products in this bulletin because of continuing changes of pesticides in the marketplace.

Figure 2—Tuber flea beetle Figure 3—Tuber flea beetle damage to foliage. damage to potato tuber. Photo courtesy of Canadian Department Photo—Ken Grey collection. of Agriculture

By A. L. Antonelli, Ph.D., Washington State University Cooperative Extension entomologist, and Roy M. Davidson, Jr., WSU Agricul- tural Research technologist, WSU Puyallup.

Use pesticides with care. Apply them only to plants, animals, or sites listed on the label. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation of the law to disregard label directions. If pesticides are spilled on skin or clothing, remove clothing and wash skin thoroughly. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

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Issued by Washington State University Cooperative Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8 and June 30, 1914. Cooperative Extension programs and policies are consistent with federal and state laws and regulations on nondis- crimination regarding race, sex, religion, age, color, creed, national or ethnic origin; physical, mental or sensory disability; marital status, sexual orientation, and status as a Vietnam-era or disabled veteran. Evidence of noncompliance may be reported through your local Cooperative Extension office. Trade names have been used to simplify information; no endorsement is intended. Revised June 2001. Subject codes 352, 270. Available online only. EB1198E